Semiconductor micro and nanofabrication lithography techniques for application in microelectronics as well as in micromechanics and optoelectronics can gain significantly from using a dry resist process, since it enables the deposition of a very uniform lithographically sensitive layer on a potentially very small area. This would otherwise be extremely difficult to achieve by using a traditional spin coated resist, such as poly(methylmethacrylate) (PMMA). We demonstrate the use of an electron sensitive sterol based evaporated electron beam resist to fabricate high-resolution features (down to 100 nm) on a small surface area. This electron beam resist has a sensitivity comparable to PMMA and is deposited using a simple thermal evaporation. Two practical applications are explored: first, this resist makes it possible to fabricate a Fresnel zone plate lens on the tip of an optical fiber in order to demonstrate the principle and the potential of highly efficient coupling of diode laser emission into the fiber; second, we use this evaporated electron beam resist in order to pattern an optical diffractive element on the facet of a semiconductor laser.
A major issue in low voltage lithography is surface charging, which
results in beam deflection presented as uneven exposure between
adjacent structures. In this study, charge-induced pattern distortions
in low-voltage energy beam lithography (LVEBL) were investigated using
a silicide direct-write electron beam lithography process. Two
methodologies have been proposed to avert charging effects in LVEBL,
namely, pattern randomizing and lithography using the crossover
voltage. Experimental results demonstrated that these methods are
effective in significantly reducing the problems associated with
charging. They indicate that charging on a sample is a function of time
interval and proximity between line structures. In addition, the
optimum time and distance between exposures for no charge-induced
pattern distortion were determined. By using the crossover voltage of
the material for lithography, charging effect can be significantly
minimized.
A process aimed at fabricating proximity x-ray lithography masks is presented. In this technique, the Ta absorber layer is deposited and patterned on the back side of the membrane and nonspin-coated electron sensitive layers were used in order to achieve high resolution patterning of this absorber. The advantages gained by this approach include a reduction of the membrane temperature during the plasma etching step of the absorber patterns without using any cooling gas. This temperature reduction results from the direct contact of the membrane with a cooling plate. This approach also allows increased protection of the absorber patterns from contamination during exposure of the mask. A third advantage is that the smooth surface of the mask exposed to the wafer in the x-ray lithography stepper may also make it possible to reduce the gap between wafer and mask, thus achieving increased resolution with the x-ray lithography process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.